Nicola Sturgeon has taken some stick today for hinting the SNP might call for another independence referendum in their 2016 Scottish parliament manifesto, despite Alex Salmond having previously said last September’s vote was a once-in-a-generation opportunity.

Cue critics taunting the SNP for pushing a ‘neverendum’ of plebiscites until they get the result they want.

But there is a perfectly principled reason why Nicola Sturgeon might want to insert a commitment to a future referendum — it’s contained within Donald Macintyre’s (excellent) article in today’s Independent:

Consider the consequences if the UK splits over EU membership, with Scotland voting yes, say, but a UK majority voting no. By now Sturgeon is likely to have led the SNP to victory in the 2016 elections and a fresh mandate for full home rule at least, and independence at most. It’s hard to imagine anything that would give her a greater casus belli for – or in – another independence referendum than a decision to withdraw from the EU against Scotland’s will. Indeed, independence would be a necessary condition of Scotland’s staying in Europe.

In such a by-no-means-impossible-to-imagine scenario of the voters of England deciding in 2017 the UK should withdraw from the EU, against the wishes of the voters of Scotland, how could anyone reasonably object to the Scots deciding if they want to remain in an EU-less UK or instead opt to become an independent nation within the EU?